2) Laser Amplified Scintillation 20 mn

P.Lindblom (on behalf of the ZEUS collaboration)

The HERA luminosity upgrade is expected to generate two major problems in the current method of luminosity determination which is based on counting brehmsstrahlung photons: damage of the calorimeter monitor due to high primary synchrotron radiation and large multiple event (pile-up) corrections.The luminosity spectrometer presented in this talk, is a novel method that reduces the impact of these problems in the luminosity measurement and is expected to yield a total systematic uncertainty of order 1%. The spectrometer counts brehmsstrahlung photon conversions in the beam pipe exit window using two small calorimeters (former ZEUS beam pipe calorimeters) symmetrically placed away from the synchrotron radiation plane. The photon conversion rate is measured by counting electron-positron (ep) coincidences in the calorimeters. The ep acceptance is measured using a third calorimeter (6 meter tagger) which tags the brehmsstrahlung electrons. The electron-positron pair is separated by a small dipole magnet.

3) Silicon Calorimeter for next Linear Collider 20 mn

H. Videau (Laboratoire de Physique des Hautes Energies Ecole Polytechnique France)

The studies held in the framework of the ECFA-DESY workshops for a linear electron collider have shown that a very dense high granularity calorimeter would be the optimal solution for studying the Higgs. A design for such a calorimeter in tungsten-silicon is presented here with some of its expected performances.

4) Extruded Plastic Scintillator for Minos collaboration 20 mn

A. Pla-Dalmaut ?

The MINOS experiment is a long-baseline, neutrino-oscillation experiment. The experiment will rely on two calorimeters: the near detector, about 1 km from the target at Fermilab; and the far detector, 730 km away in northern Minnesota. Both detectors use 2.5 cm of steel per sample as converters, plastic scintillator as the active elements and wavelength-shifting fiber readout. Overall the two calorimeters will require almost 300 tons of plastic scintillator. Currently available plastic scintillating materials are high quality products whose cost is relatively expensive. As a way of lowering the costs, extruded plastic scintillator is being produced using commercial grade polystyrene pellets. MINOS utilizes an extruded plastic scintillator bar (10 mm by 41 mm cross section) with a 2-mm deep groove for a wavelength-shifting fiber for readout. The scintillator strip has a co-extruded TiO2 coating which acts as reflector and provides ruggedness allowing the strips to be glued directly into aluminum panels. Multi-anode PMT and multiplexing are used for the readout. Development of the extruded plastic scintillator will be described including the selection of raw materials, extrusion process and QC techniques.

A luminosity Spectrometer for ZEUS 20 mn

S. Paganis (USA)

The HERA luminosity upgrade is expected to generate two major problems in the current method ofluminosity determination which is based on counting brehmsstrahlung photons: damage of the calorimeter monitor due to high primary synchrotron radiation and large multiple event (pile-up) corrections.The luminosity spectrometer presented in this talk, is a novel method that reduces the impact of these problems in the luminosity measurement and is expected to yield a total systematic uncertainty of order 1%. The spectrometer counts brehmsstrahlung photon conversions in the beam pipe exit window using two small calorimeters (former ZEUS beam pipe calorimeters) symmetrically placed away from the synchrotron radiation plane. The photon conversion rate is measured by counting electron-positron (ep) coincidences in the calorimeters. The ep acceptance is measured using a third calorimeter (6 meter tagger) which tags the brehmsstrahlung electrons. The electron-positron pair is separated by a small dipole magnet.